Understanding nitrogen and its impact on water

High Nitrogen Levels and Eutrophication

When there’s a lot of total nitrogen in water, it often leads to problems like algal blooms, including toxic blue-green algae, and overgrowth of aquatic plants. This process, called eutrophication, can create conditions where the water no longer supports aquatic life.

How Nitrogen Enters the Environment

Most total nitrogen gets into the environment through runoff and streamflow, but wind can also play a role. Human activities also contribute to nitrogen levels.

Where Nitrogen Ends Up

In rivers and lakes, inorganic nitrogen compounds like ammonia, nitrate, and nitrite promote algal growth. High levels of total nitrogen and phosphorus, combined with favorable conditions, can cause algal blooms. Algae use the nitrogen, and when they die, nitrogen is released back into the water in different forms through processes like mineralization and nitrification.

Natural waters usually contain significant amounts of organic nitrogen and nitrate, but less ammonia or nitrite. Two key processes that affect nitrogen levels are denitrification and nitrification. Denitrification by bacteria breaks down nitrate into nitrogen gas, which is then lost to the atmosphere. Conversely, some blue-green algae can convert dissolved nitrogen gas back into nitrate, a process called nitrogen fixation.

Environmental Guidelines

Several factors affect algal growth, so it’s tricky to set a specific safe level of total nitrogen. However, here are some general guidelines:

  • Rivers and Streams: 100-750 micrograms/L
  • Lakes and Reservoirs: 100-500 micrograms/L
  • Estuaries and Embayments: 10-100 micrograms/L (as nitrate-nitrogen)
  • Coastal Waters: 10-60 micrograms/L (as nitrate-nitrogen)

Future guidelines will likely use a risk-based approach, considering various influencing factors.

Sources of Nitrogen Emissions

Industry Sources:

  • Food processing plants
  • Sewage treatment plants
  • Garbage leachate
  • Intensive livestock operations

Diffuse Sources:

  • Runoff from agricultural land
  • Fertilizers and manures
  • Urban runoff

Natural Sources:

  • Soil, plant, and animal material

Transport Sources:

  • Exhaust emissions from vehicles

Consumer Products:

  • Foods like spinach, beetroot, lettuce, and preserved meats
  • Lawn and garden fertilizers
  • Some household cleaners

Nitrogen in various forms is common in our environment, and managing its levels is crucial to maintaining healthy water systems. Get in touch with our team to find out how Eco Detection’s Ion-Q+ can automate the monitoring of nitrogen levels to help you with your management strategy. sales@ecodetection.com